SIMULATION OF A MULTIUSER CDMA SYSTEM

Abstract

This dissertation presents the performance of CDMA system in terms of probability of error versus SNR on varying various parameters like number of users, number of chips ( number of bits of signature sequence), paths (single path, multipath). Signature sequence is the second name of the code which is assigned to each user. The bit error probability is defined as the probability of the total number of different received bits to the transmitted bits. As an alternative to analytical approach a simulation has been used to analyze the performance of the multiuser CDMA system. The simulation approach uses a Monte Carlo simulation to produce the reasonable probability of error versus signal to noise ratio results. The variation of the number of chips is taken as the main criteria for evaluation of the probability of error versus SNR. First simulation is done to obtain probability of error for desired user is synchronized with receiver. Effect of number of chips, number. of users in the system, on the performance of the multiuser CDMA system have been observed. Second- simulation is done to obtained the probability of error versus SNR for the desired user is not synchronized with the receiver. Effect of number of chips, number of users in the system, on the performance of the multiuser CDMA system have been observed. Performance is assessed with variation of number of interferers (i.e. users in the system except desired user). Effect of orthogonality of signature sequence is also seen.